Circuit breaker



Jan. 17, 1950 l.. F.-GEREM1A CIRCUIT BREAKER Filed Sept. 14, 1948 wir, \\\\\\\\W///////7////////////////// nlm Inventor Leo F Geven/1 ia Patented Jari. 17, 1950 2,494,868 CIRCUIT BREAKER Leo F. Geremia, Wallingford, Conn., assignor t The Trumbull Electric Manufacturing Company, Plainville, Conn., a corporation of Connecticut Application September 14, 1948, Serial No. 49,231

11 Claims.

My invention relates particularly to the type of circuit breaker which can be opened and closed by hand as well as automatically m case of an overload and reset manually.

The main object of my invention is to provide a simple and reliable mechanism of the overcenter spring and releasable tripping-cradle type in which latch-pressure is reduced to a minimum but which is nevertheless very positive in its automatic opening movement.

Another object of my invention is to provide a simple and reliable mechanism in which adequate contact pressure is obtained without excessive resistance to the automatic tripping action.

Another object is to provide a circuit breaker having energy storagev means normally opposing tripping, but which on overload shifts its action so as to assist tripping.

Fig.. 1 is a plan view of a circuit breaker involving one form of my invention, parts being broken away and part of the casing shown in section.

, Fig. 2 is a sectional view of the casing on the plane of the line 2-2 of Fig. l, and showing a sideview of the mechanism, parts being broken away and the switch being in the closed circuit or on position.

Fig. 3 is a sectional view taken on the plane of the line 3-3 of Fig. 2.

Fig. 4 is a sectional view on the plane of th line 4-4 of Fig. 2.

Fig. 5 is a view similar to Fig. 2 but the switch is shown in the open circuit or. off position after manual operation.

Fig. 6 shows a fragment of the casing cover in section and with the parts of the switch in the open circuit position after automatic tripping.

Fig. 7 is a detail side view of the trip member.

In the form' shown, the mechanism is enclosed in a casing consisting of the body part I0 and the cover II. The circuit terminals I2 and I3 are mounted in the body of the casing and project externally for attachment of the binding posts etc. The stationary contact I4 is connected to the terminal I2. In this form of construction, all of the parts of the circuit breaker except the overload release are carried by a bracket I5 which is supported by screws I6 in the top or cover of the casing.

The trip member I1 is pivoted on the shaft I8 supported in the bracket. The rocker I9 is pivoted at 20 in the bracket and adapted to be actuated manually by the handle or finger piece 2I.

. rocker member I9.

The switch member 22 has a blade-like pivot, member 23 which is hinged in an opening 24 in the trip member Il. The spring 25 connects the rocker I9 to the switch member at the anchorage 22.

The thermostatic bimetal member 26 is supported by the terminal member I3 and connected by ilexible lead 21 to the switch member 22. During the normal manual operation the tip 28 of the trip member engages the tip of the thermostatic member as shown in Figs. 2 and 5 where the spring 25 biases the trip member clockwise as viewed in Figs. 2, 5 and 6.

The auxiliary spring 29 normally partially counteracts or opposes the action of the spring 25 and for this purpose is mounted on a rod 3U which is pivoted at 3| and is slidably connected with an arm Il' of the trip member I'l. This pivot 3| serves as an abutment for the spring device so that it' reverses its action when the breaker is tripped.

The member 32 which has its outer surface formed as a segment of a cylinder is formed of insulating material and constitutes a part of the In passing to the ofi position of Fig. 5, the toggle action of the spring 25 tends to rotate the rocker member I9 counter clockwise and the member 32 abuts against the shoulder 33 on the trip member I'l.

In the form shown, the trip member has three arms radially separated around its pivot axis I8 with the overload latching member 28 at the end of one arm, the auxiliary spring device connected to another arm and the shoulder 33 on the third arm.

The right hand end of the slot in the cover forms an abutment 34 for the finger piece when the parts are moved to the closed circuit position.

The stop member 35 serves as an abutment for the trip member in the position of Fig. 6. The stop 3E serves as an abutment for the switch contact member 22 in the open circuit position.

In the on position of Fig. 2 and the oi position of Fig. 5, the trip member -I1 remains stationary. The spring 25 is under tension in both positions since one end yof the spring pulls against the anchorage 22' on the switch member 22 and thus presses the pivot blade 23 into the left hand end of the opening 24 in the trip member which is mounted on the pivot pin I8 in the bracket I5 and the other end of the spring is anchored to the left lower corner of the rocker I9 which is pivoted to the bracket I5 at 20, thus biasing the 3 tip 28 of trip member I1 against the tip ot the thermostatic bimetal arm 28.

To open the circuit from the position of Fig. 2, the handle or `finger piece 2| is moved toward the left from the position of Fig. 2 to that oi F18. 5. This carries the left end of spring 25 past the pivot blade 23 so that the spring throws the right hand end 22' below the pivot 20 and snaps the switch member from the position of Fig. 2 to that of Fig. 5, where the switch contact member abuts against the stop 36.

To close the circuit, the finger piece is moved l from the position of Fig. 5 to that of Fig. 2 and the action is reversed, the switch member engaging the contact Il.

It the circuit is closed and a sumcient overload heats the bimetal or thermostatic member 26, it will warp downwardly from the position of Fig. 2

so that it will dlsengage from the tip z8 of the trip member I1. The tension of the spring 25 then becomes effective through its pull on 22' to turn the trip member from the position of Fig. 2 to that of Fig'. 6 and break the circuit and the linger piece 2| will be left in a position intermediate the ends of the slot in the cover indicating that the switch has been tripped automatically.

It will be seen that the principal component of the spring tension is exerted to turn the trip member against the bimetal strip and a much smaller component tends to hold the switch member 22 in the closed circuit position. Ordinarily in this type of circuit breaker, it is necessary to use a very strong spring in order to get suilcient contact pressure. This produces excessive pressure at the end of the trip member. I have discovered-that I can use a more powerful spring pressure for the switch action by employing the supplemental spring 29 which in the closed circuit position tends to counteract spring 25 and bias the trip member l1 away from strip 26 and thus relieve the trip engagement pressure. Notwithstanding this action, the spring 29 by toggle action reverses its pressure shortly after the trip is released and moves to the position of Fig. 6, so that the auxiliary spring device then augments the action of the main spring.

After the switch has been automatically tripped to the position of Fig. 6, it may be reset by simply turning the finger piece with the rocker I9 back to the off position of Fig. 5 whereupon the tip 28 of the trip member will re-engage the end of strip 26 provided of course that the bimetal has cooled sufficiently to permit it.

It should be understood that the overload release may be suitably actuated magnetically in case of a sudden excessive overload.

. I claim:

1. In a circuit breaker, a bracket, a trip member pivoted in said bracket, a stationary contact, a switch member pivoted in said trip member, for coacting with said contact a manually operable rocker pivoted in said bracket, a main spring connected in tension between said rocker and said switch member in position to press it against said contact and to swing said switch member from an on to an oil position when the rocker is turned in one direction on its pivot, an overload member acting normally as an abutment for the trip member and in case of an overload in the circuit to release the trip member and cause the trip member to turn by reason oi the tension of said spring and an auxiliary toggle acting spring normally coacting with said trip member in partial opposition to the main spring and aug- 4 inenting the action or the main spring when the trip member is released.

2. In a circuit breaker, a bracket, a trip member pivoted in said bracket, a switch member pivoted in said trip member, a manually operable rocker pivoted in said bracket, a main spring connected between said rocker and said switch member in position to swing said switch member from an on to an oir position when the rocker is turned on its pivot, an overload member acting normally as an abutment for the trip member and in case of an overload in the circuit to release the trip member and cause the trip member to turn and a toggle acting auxiliary spring device coacting with said trip member in partial opposition to the main spring when in the normal latching position of the trip member and having an abutment in position to cause the direction oi' its pressure to be reversed when the circuit is broken automatically.

3. In a circuit breaker, a stationary contact, a pivotally movable contact, means in common for moving said movable contact manually and automatically including a main spring and an overload release device having a bimetal arm and a trip member interlocked together under pressure of said spring, said spring being arranged to exert its greater Iorce in rotating said movable contact and a lesser iorce in holding the contacts together and a separate toggle acting spring for opposing the action of said ii'rst-named spring upon said interlock and augmenting the action of the main spring when the trip member is released.

4. In a circuit breaker, a pivoted trip member having three arms, an independently pivoted manually operated rocker, a switch member hinged in one arm of said trip member, a stationary contact, a main toggle acting spring connecting said rocker and said switch member and biased to turn the trip member in one direction, an overload actuated latch normally coacting with another arm of said trip member and holding the trip member from turning and retracted upon an overload to release the trip member and an auxiliary toggle acting spring exerting a pressure on the third arm of said trip member in opposition to the pressure Vof the' main spring prior to release of the trip member and suppleinenting the main spring ai'ter release of the trip member,

5. In a circuit breaker, a bracket, a. trip member pivoted to said bracket, a stationary Contact, a switch member pivoted in said trip member, for coacting with said contact. a manually operable rocker pivoted in said bracket, a, main spring connected in tension between said rocker and Said switch member in position to press it against said contact and to swing said switch member from an on to an oil' position when the rocker is turned in one direction on its pivot, an overload member acting normally as an abutment for thetrip member and in case of an overload in the circuit to release the trip member and cause the trip member to turn by reason of the tension of said spring, an auxiliary spring normally coacting with said trip member in partial opposition to the main spring and means for reversing the direction of application of the spring when the trip member is released.

6. In a circuit breaker, a pivoted trip member having three arms extending radially outward from its pivot, an independently pivoted manually operated rocker, a switch member hinged in a,494,aca

one arm of said trip` member, a main toggle acting spring connecting said rocker and said switch member and biased to turn the trip member in one direction, an overload actuated latch normally coacting with another arm of said t.ip member and holding the trip member from turning and an auxiliary spring exerting a pressure on the third arm of said trip member in opposition to the impulse of the main spring and means for reversing the direction of pressure of the spring when the trip member is released.

7. In a circuit breaker, a manually operable rocker, a pivoted trip member, a switch contact member pivoted to said trip member, a main spring connecting said switch contact member to said rocker and biasing said trip member to.turn in one direction, an overload release member normally opposing such turning oi the trip member, said spring serving to bias the switch contact member to a closed circuit position when the rocker is in one position and to bias the switch contact member to an open circuit position when the rocker is in another position and an auxiliary toggle spring device pivoted at one end and coacting at its other end with the trip member to oppose the action of the main spring when the overload release member holds the trip member from turning and to augment the action of the main spring when the overload device releases the trip member.

8. In a circuit breaker, a stationary contact, a manually operable rocker, a pivoted trip member, a switch contact member pivoted to said trip member for energizing said stationary contact to close a circuit, a main spring connecting said switch contact member to said rocker and biasing said trip member to turn in one direction, an overload release member normally opposing such turning of the trip member, said spring serving to bias the switch contact member to engage said stationary contact when the rocker is in one position and to bias the switch contact member away from said stationary contact when the rocker is in another position and an auxiliary toggle spring device anchored at one end and coacting at its other end with the trip member to oppose the action of the main spring when the overload release member holds the trip member from turning and to augment the action of the main spring when the overload device releases the trip member and a stop to limit the opening movement of the switch contact member.

9. In 'a circuit breaker, a manually operable rocker, a pivoted trip member, a switch contact member pivoted to said trip member, a main spring connecting said switch member to said rocker andbiasing said trip member to turn in one direction, an overload release member normally opposing such turning of the trip member, said spring serving to bias the switch contact member to a closed circuit position when the rocker is in one position and to bias the switch contact member to an open circuit position when the rocker is in another position and an auxiliary toggle spring device supported at one end and coacting at its other end with the trip member to oppose the action of the main spring when the overload release member holds the trip member from turning and to augment the action of the main spring when the overload device releases the trip member and means of connection between the rocker and the trip member for resetting the trip member.

10. In a circuit breaker, a manually operable rocker, a pivoted trip member, a switch contact member pivoted to said trip member, a main spring connecting said switch contact member to said rocker and biasing said trip member to turn in one direction, an overload release member normally opposing such turning of the trip member, said spring serving to bias the switch contact member to a closed circuit position when the rocker is in one position and to bias the switch contact member to open circuit position when the rocker is in another position and an auxiliary toggle spring device anchored at one end and coacting at its other end with the trip member to oppose the action of the main spring when the overload release member holds the trip member from turning and augmenting the action of the main spring when the trip member is released and stops to limit the movement of the trip member and the switch contact when the trip member is released.

11. In a circuit breaker, a manually operable rocker, a pivoted trip member, a switch contact member pivoted to said trip member, a main spring connecting said switch contact member to said rocker and biasing said trip member to turn in one direction, an overload release member normally opposing such turning of the trip member, said spring serving to bias the switch contact member to a closed circuit position when the rocker is in one position and to bias the switch contact member to an open circuit position when the rocker is in another position and an auxiliary toggle spring device anchored at one end and coacting at its other end with the trip member to oppose the action of the main spring when the overload release member holds the trip member from turning and to augment the action of the main spring when the overload device releases the trip member and stops to limit the movement of the trip member and the switch contact member when the trip member is released.

LEO F. GEREMIA.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,357,210 Leonard Aug. 29, 1944 2,360,682 Hutt Oct. 17, 1944 

